Heavy duty shears of the type powered by hydraulic cylinders have proven extremely useful in handling metal scrap of various sorts. Such scrap may be in the form of pipe made of steel, soft iron or cast iron; structural beams such as I beams, channels and fabricated girder beams; rods and heavy cables having diameters up to three inches; and larger metal sheets and plates and metal pieces that are cast, roll stamped or otherwise formed.
Typically, heavy duty shears such as those illustrated in U.S. Pat. No. 4,519,135 can be mounted on the dipper stick of a back hoe so that they may be controlled fairly well in handling various types of scrap. However, such shears have numerous disadvantages, such as not permitting the shear to be used as efficiently and rapidly as may be desired, considering the amount of scrap that must be reduced in size for further processing. A significant advance in the art would result if heavy duty shears could be developed that completed the desired result quickly and efficiently.
Moreover, the shearing and crushing surfaces of present-day hydraulic shears are susceptible to destructive wear and to the loss of the clean cutting surface during extended use. It would be useful to find a means to extend the useful life of such shearing attachments, and to improve the ease of replacing such attachments.